Method for surface treating metal substrate

ABSTRACT

A method of treating a metal substrate comprise the steps of: anodizing the metal substrate to create pores on the surface of the substrate; and treating the metal substrate by NCVM to form a NCVM coating on the surface of the substrate.

BACKGROUND

1. Technical Field

The disclosure relates to a method for surface treating metal substrates.

2. Description of Related Art

Typically, to improve external appearance and quality of a housing of a portable electronic device, a surface treatment (e.g., Non Conductive Vacuum Metallization, NCVM) can be applied.

However, it can be difficult to treat alloy housings by the NCVM process because the surface of the housing is usually too smooth.

Therefore, there is room for improvement in the art.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the present method for surface treating a metal substrate can be better understood with reference to the following drawings. These drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present method. Moreover, in the drawings like reference numerals designate corresponding parts throughout the several views. Wherever possible, the same reference numbers are used throughout the drawings to refer to the same or like elements of an embodiment.

The drawing is a flow chart of a surface treatment method according to an exemplary embodiment.

DETAILED DESCRIPTION OF THE EMBODIMENTS

What is described below is a method for surface treating a metal substrate. For purposes of illustration and description, an alloy housing of an electronic device is used. However, the exemplary embodiment is not limited to alloy housings, but can also be applied to other metal substrates that need to be processed using NCVM. [0008]

Referring to the drawing, the method may include the following steps: (S1), providing a metal substrate; (S2), trimming the metal substrate; (S3), anodizing the metal substrate; (S4), treating the metal substrate using NCVM process.

In step S1, a metal substrate is provided and formed into a housing pre-form by die-casting, punching, or forging. The metal substrate may be magnesium alloy or aluminum alloy.

In step S2, the housing pre-form is trimmed to form a base housing. Then, the base housing may be degreased using a trichloroethylene solution.

In step S3, The base housing is anodized to form an anodic coating on an external surface of the substrate. The anodic coating creates tiny pores on the external surfaces of the substrate. Anodizing may be done using sulphuric acid, orthophosphoric acid, or chromic acid.

In step S4, the base housing is treated using a NCVM process to form an NCVM coating on the anodic coating. Thus, an alloy housing is manufactured.

Because tiny pores can be formed in the surface of the base housing by anodizing, the NCVM coating may partially fill the pores to interlock with the external surface of the alloy housing.

It is to be understood, however, that even through numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. 

1. A method of treating a metal substrate, comprising: anodizing the metal substrate to create pores on the surface of the substrate; and treating the metal substrate by NCVM to form a NCVM coating on the surface of the substrate.
 2. The method as claimed in claim 1, wherein the metal substrate is magnesium alloy or aluminum alloy.
 3. The method as claimed in claim 1, wherein the anodizing step is performed using sulphuric acid, orthophosphoric acid, or chromic acid.
 4. The method as claimed in claim 1, further comprising a step of degreasing the metal substrate before the step of anodizing.
 5. The method as claimed in claim 4, wherein the step of degreasing is performed using trichloroethylene solution. 